Method for improving electromigration performance of metallization features through multiple depositions of binary alloys

Abstract

The reliability and electromigration performance of planarized metallization patterns in an electrical device, for example copper, inlaid in the surface of a layer of dielectric material overlying a semiconductor substrate, are enhanced by a method for more reliably and uniformly diffusing into a conductive fill alloying elements which reduce or substantially prevent electromigration. The method comprises depositing around a conductive fill metal alloy films and alloying layers comprising one or more alloying elements having physical and/or chemical attributes which are effective for minimizing or substantially preventing electromigration along grain boundaries and/or along the interface between the surfaces of the conductive fill and other surfaces. The metal alloy films and alloying layers are advantageously deposited where their particular physical and/or chemical attributes may be most beneficial for improving electromigration performance. The alloying elements may then be diffused into the conductive fill to effect alloying therewith.

What is claimed is:  
     
         1 . A method of manufacturing an electrical device, the method comprising: 
 providing a substrate comprising a dielectric layer having a recess therein;    forming at least one metal alloy film on surfaces of the recess;    forming a conductive fill over the at least one metal alloy film;    planarizing the conductive fill and the dielectric layer;    forming at least one alloying layer comprising at least one alloying element on the conductive fill; and    diffusing an amount of the at least one alloying element from the at least one alloying layer into the conductive fill.    
     
     
         2 . The method recited in  claim 1 , further comprising removing at least a portion of the at least one alloying layer from the conductive fill.  
     
     
         3 . The method recited in  claim 1 , wherein the at least one metal alloy film comprises two or more alloying elements and wherein the method further comprises diffusing an amount of the two or more alloying elements from the at least one metal alloy film into the conductive fill.  
     
     
         4 . The method recited in  claim 3 , wherein the two or more alloying elements of the at least one metal alloy film comprise at least one alloying element that reduces electromigration of the conductive fill along grain boundaries of the conductive fill.  
     
     
         5 . The method recited in  claim 3 , wherein the two or more alloying elements of the at least one metal alloy film comprise at least one alloying element that reduces electromigration of the conductive fill at an interface of the conductive fill and another surface.  
     
     
         6 . The method recited in  claim 3 , wherein the two or more alloying elements of the at least one metal alloy film comprise at least one alloying element that reduces electromigration of the conductive fill along grain boundaries of the conductive fill and at least one different alloying element that reduces electromigration of the conductive fill at an interface of the conductive fill and another surface.  
     
     
         7 . The method recited in  claim 3 , wherein the two or more alloying elements of the at least one metal alloy film comprise at least one alloying element that reduces diffusion of the conductive fill into a surrounding dielectric.  
     
     
         8 . The method recited in  claim 1 , wherein the at least one alloying layer comprises two or more alloying elements.  
     
     
         9 . The method recited in  claim 8 , wherein the two or more alloying elements of the at least one alloying layer comprise at least one alloying element that reduces electromigration of the conductive fill along grain boundaries of the conductive fill.  
     
     
         10 . The method recited in  claim 8 , wherein the two or more alloying elements of the at least one alloying layer comprise at least one alloying element that reduces electromigration of the conductive fill at an interface of the conductive fill and another surface.  
     
     
         11 . The method recited in  claim 8 , wherein the two or more alloying elements of the at least one alloying layer comprise at least one alloying element that reduces electromigration of the conductive fill along grain boundaries of the conductive fill and at least one different alloying element that reduces electromigration of the conductive fill at an interface of the conductive fill and another surface.  
     
     
         12 . The method recited in  claim 8 , wherein the two or more alloying elements of the at least one alloying layer comprise at least one alloying element that increases adhesion at an interface of the conductive fill and another surface.  
     
     
         13 . The method recited in  claim 1 , wherein the at least one metal alloy film comprises a stack of two or more metal alloy films, each comprising at least one alloying element.  
     
     
         14 . The method recited in  claim 13 , wherein at least one of the two or more metal alloy films comprise at least one alloying element that reduces electromigration of the conductive fill along grain boundaries of the conductive fill.  
     
     
         15 . The method recited in  claim 13 , wherein at least one of the two or more metal alloy films comprise at least one alloying element that reduces electromigration of the conductive fill at an interface of the conductive fill and another surface.  
     
     
         16 . The method recited in  claim 13 , wherein at least one of the two or more metal alloy films comprise at least one alloying element that reduces electromigration of the conductive fill along grain boundaries of the conductive fill and at least one different alloying element that reduces electromigration of the conductive fill at an interface of the conductive fill and another surface.  
     
     
         17 . The method recited in  claim 13 , wherein at least one of the two or more metal alloy films comprise at least one alloying element that reduces diffusion of the conductive fill into a surrounding dielectric.  
     
     
         18 . The method recited in  claim 1 , wherein the at least one metal alloy film comprises a copper alloy film.  
     
     
         19 . The method recited in  claim 1 , wherein the at least one alloying layer comprises a stack of two or more alloying layers, each comprising at least one alloying element.  
     
     
         20 . The method recited in  claim 1 , wherein the conductive fill comprises copper.  
     
     
         21 . The method recited in  claim 1 , wherein the at least one alloying layer is formed by a physical vapor deposition (PVD) process.  
     
     
         22 . The method recited in  claim 21 , wherein the at least one alloying layer is formed by one of sputtering, ion plating, electroplating, and vacuum evaporation.  
     
     
         23 . The method recited in  claim 1 , wherein the conductive fill and the dielectric layer are planarized by a chemical-mechanical polishing (CMP) process.  
     
     
         24 . The method recited in  claim 1 , wherein the amount of the at least one alloying element is diffused from the at least one alloying layer into the conductive fill by an annealing process.  
     
     
         25 . The method recited in  claim 2 , wherein the portion of the at least one alloying layer is removed from the conductive fill by a chemical-mechanical polishing (CMP) process.  
     
     
         26 . The method recited in  claim 1 , wherein the electrical device comprises a semiconductor integrated circuit device; and 
 wherein the substrate comprises a semiconductor material comprising one of monocrystalline silicon (Si) and gallium arsenide (GaAs).    
     
     
         27 . The method recited in  claim 1 , wherein the at least one alloying element of the at least one alloying layer is selected from the group consisting of zirconium (Zr), tin (Sn), boron (B), magnesium (Mg), carbon (C), palladium (Pd), cobalt (Co), nickel (Ni), and cadmium (Cd).  
     
     
         28 . The method recited in  claim 3 , wherein the two or more alloying elements of the at least one metal alloy film are selected from the group consisting of magnesium (Mg), calcium (Ca), tin (Sn), boron (B), carbon (C), palladium (Pd), cobalt (Co), nickel (Ni), zirconium (Zr), and cadmium (Cd).  
     
     
         29 . The method recited in  claim 1 , further comprising: 
 forming at least one additional alloying layer comprising at least one alloying element on the conductive fill after removing the at least one alloying layer from the conductive fill;    diffusing an amount of the at least one alloying element from the at least one additional alloying layer into the conductive fill; and    removing the at least one additional alloying layer from the conductive fill.